The invention has as its object an apparatus for the correction of the relative position between the maxillary and the mandibular jaws. The apparatus comprises a first guiding element and a second guiding element, with the two elements initially disengaged from each other when the jaws are in an open position. The two guiding elements come together in cooperating contact when the maxillary and mandibular jaws are between a pre-set intermediate closure position and a complete closure position. The two elements are mounted in lateral position in correspondence with the dental arch by means of fasteners.
There are presently known devices of this construction, in which the two elements come into reciprocal contact that prevents the patient from completely closing the mandibular jaw against the maxillary one when the two jaws are in an incorrect position. Generally, the correction relates to relative positioning of the mandibular and the maxillary jaws in the antero-posterior direction; that is, they relate to a forward displacement or to a backward displacement of the mandibular jaw relative to the maxillary jaw, with respect to the correct closure position.
The two reciprocally stopping elements compel the patient to consciously move his mandibular jaw into the correct position when he wishes to close that jaw against the maxillary one. Otherwise, the two stops keep the mandibular jaw at a certain distance from the maxillary one, preventing the closure and therefore the mastication.
Such a device therefore is a passive device, and it depends on the patient correcting the position of his own free will to set forth the function of mastication, for example, or simply to close his mandibular jaw against his maxillary jaw. There is therefore no control of the correction, whether to ensure that the same occurs safely, or to make sure that the forward or backward displacement takes place progressively, accustoming the patient to assume the correct mandibular position. Furthermore, the known apparatuses are not capable of also guaranteeing the arising of pressure in directions different from the antero-posterior ones, especially vertical or transverse positions relative to the antero-posterior one.
The purpose of the present invention is to provide an apparatus of the type described at the beginning, that overcomes the drawbacks of the present passive apparatuses by actively supplying an action of guided displacement of the mandibular jaw relative to the maxillary one, while maintaining the construction and convenience advantages of the known apparatuses.
The invention has the further purpose to permit not only action of forward displacement of the mandibular jaw relative to the maxillary one, but on the contrary, also actions of displacement of the maxillary jaw relative to the mandibular one, supplying an action of distraction on the natural maxillary sutures (lines of junction).
The invention achieves the above-mentioned purposes with a device of the type described at the beginning, in which the two elements are configured such that from the above-mentioned intermediate closure position of the jaws the two elements come into reciprocal contact and slide relatively to each other, thereby exerting together and automatically a push in a direction of relative displacement between the maxillary and the mandibular jaws for the assuming of the correct relative position between the maxillary and the mandibular jaws by the forward displacement of one of them over the other, or vice-versa.
The two guiding elements can be affixed to the dental arches by any type of anchoring elements.
Advantageously, the maxillary jaw and the mandibular jaw are provided with a pair of elements placed on the opposite sides of the antero-posterior axis.
These elements may be mounted on apparatuses of the removable type or on fasteners of the permanent type affixed to the dental arches.
The pair of guiding elements of the maxillary and mandibular jaws, together with their fasteners, may be part of a common supporting and application structure. For example, the fasteners may be connected by means of structures using wires or the like.
The anchorings may be placed directly on one or more teeth of the corresponding arch, either in the form of annular bands that surround the tooth, or in the form of fasteners glued to one or more teeth. Alternatively, the anchorings may be in the form of structures of a type similar to that of removable orthodontic apparatuses. The structural elements that connect the fasteners together may be wires or the like, which are welded to the fasteners or affixed to the same in a movable manner, e.g., by means of thin iron wires or elastics. The structures further may comprise combinations of these fasteners.
According to a variant, said structures may also incorporate other types of operative units for orthodontics, which together with the action of the apparatus object of the invention, provide other corrective functions. For example, the structure may be constructed to provide a divaricating action in a direction transverse to the antero-posterior axis, displacements of the teeth, or other. The structure may also be designed to absorb or in some way regulate or generate forces in a vertical direction, that otherwise the apparatus according to the invention is not capable of generating.
Obviously the two elements associated with the mandibular and with the maxillary jaws, and their relative anchoring elements, can be completely disconnected between them.
According to a further advantageous improvement, the guiding elements may be mounted in a fixed manner, or they may be adjustable in relative position at least in one direction, especially in the antero-posterior direction, and blockable (or lockable) in that position.
These further improvements result from said elements being mounted on sliding guides engaged on the guides connected to the anchoring elements, there being provided limiting stops displaceable and blockable in position, in a movable manner at least in one of the two sliding directions.
It is also possible to provide for elastic means that are inserted between stop or collision points (that are fixed or adjustable in position) and these guiding elements. The elastic means maintain the guiding elements in position with a certain elastic giving force. In this case, the displacement action is further dampened by the yielding quality of the elastic element, relative to a stable but regulatable positioning of the guiding elements.
A further characteristic of the invention is that, in combination with the guiding element, it is possible to provide for elastic elements that resist the closure action of the mandibular jaw against the maxillary jaw (i.e., that act in a direction opposed to this closure displacement). These elastic elements that resist closure action of the jaws are constituted by springs associated with the mandibular jaw and/or with the maxillary jaw and of the stop elements associated with the maxillary or mandibular jaws. Also in the case of these elastic elements that resist the closure of the maxillary jaw against the mandibular jaw, the elements associated with the maxillary jaw and those associated with the mandibular jaw are initially not in engagement with one another; and they enter into action only at a certain point of the closure function. Similarly to the guiding elements, these elastic elements that oppose or resist the closure of the mandibular jaw against the maxillary jaw are arranged in a laterally offset position relative to the teeth of the corresponding arch. These elements have the function of supplying simultaneous moments (i.e., forces) in a direction perpendicular or transverse to the occlusion plane of the dental arches, on the individual dental elements and/or on the bone bases. Such intrusion movements may be necessary to correct errors in placement in the closure position of the two dental arches.
Even though the apparatus according to the invention has heretofore been described with reference to corrective displacements in a direction of the anteroposterior axis, it is obvious that with relatively simple modifications, it is also possible to apply the same construction and the same principle to make corrections in a direction transverse to the antero-posterior axis.
With reference to the above description and especially to the fact that at least one of the two cooperating guiding means associated with the mandibular and maxillary jaws is adjustable with respect to the relative positioning of the two guiding means, it is possible not only to obtain a correction in the antero-posterior direction, but also a correction in the angular direction relative to an axis perpendicular to the antero-posterior direction. In fact, by regulating the position of the guiding means on the two sides of the central antero-posterior axis in a non-symmetrical manner, the mandibular jaw will be subjected to displacements that are different on one side relative to the other side, thus obtaining also a certain rotation of the same and therefore a certain correction of at least one component transverse to the antero-posterior direction.
The guiding elements according to the invention do not generate any force component in the vertical direction, that is to say in a direction transverse to the occlusion axis. Such action may be exerted by integration or combination structures provided to that end in combination with the present guiding elements.
Further improvements of the invention constitute the object of the dependent claims.